The present invention relates to improved process for producing a film of Sm (samarium)-Co(Cobalt) alloy, and more particularly relates to an improvement in production, by means of plating, of a Sm-Co alloy film well suited to magnetic applications such as magnetic recording media.
Production of Sm-Co alloy films is conventionally carried out by sputtering and vacuum evaporation. Such conventional processes are in general very high in cost of installation but rather low in productivity. In addition, these conventional processes are quite unsuited for production of Sm-Co alloy films on intricate and/or large configurations.
As a substitute for such defective processes, wet-plating process has recently been proposed. For example, see pages 30 and 31 of "the Summary of Lectures at the 72nd Academic Seminar" issued by the corporation aggregate, Institute of Metal Surface Technology in Japan. This newly proposed process is carried out in a non-aqueous plating bath which includes samarious nitrate and cobalt nitrate dissolved with propylene carbonate. In this case, however, the nitrates used both contain crystal water. As a consequence, aqueous component is inevitably contained in the plating bath through dissolution of the nitrates. It is generally known that presence of such aqueous component in a plating both of non-aqueous solvent disturbs smooth electrocrystallization of base metal such as Sm-Co alloy. So, no plated film of high qualities can be obtained by such a wet-plating process.